Hello. Construct3 has a wonderful debugging mode.
Please feel free to use it.
Here is an example of your problem.
We launch and pause, and in order to see everything better, we can slow down time. (Green)
Then we look where the objects with which the hero encounters and dies.
We see that object number 5 is invisible and has physics behavior enabled and motion enabled. This object falls down under gravity. Our hero collides with him and dies. (Blue)
This is how the debug mode helped us quickly find the problem. For example, you can turn off his mobility.